package STO_25;

import LCommon.ListNode;

public class Solution {
	public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
		ListNode head = new ListNode(1);
		ListNode ret = head;
		while (l1 != null && l2 != null) {
			if (l1.val < l2.val) {
				head.next = l1;
				l1 = l1.next;
			} else {
				head.next = l2;
				l2 = l2.next;
			}
			head = head.next;
		}
		head = l1 == null ? l2 : l1;
		return ret;
	}

	public ListNode mergeTwoLists_recur(ListNode l1, ListNode l2) {
		if (l1 == null) {
			return l2;
		}
		if (l2 == null) {
			return l1;
		}
		if (l1.val <= l2.val) {
			l1.next = mergeTwoLists_recur(l1.next, l2);
			return l1;
		}else {
			l2.next = mergeTwoLists_recur(l1, l2.next);
			return l2;
		}
	}

}
